1. Field of the Invention
The invention relates to a method for testing the transmission states of a device for wireless communication.
2. Discussion of the Background
Digital mobile radio devices and also other devices for wireless communication are becoming ever more complex and increasingly have at their disposal transmission parameters which can be adapted to the channel quality and which enable a plurality of transmission states merely by reason of practical combinations thereof. The channel quality describes the quality of the physical transmission channel. The transmission state which is to be adjusted is selected by means of an item or items of decision information, e.g. of a measured transmission quality, which is/are transmitted by the mobile radio device. In the development of these devices which are becoming ever more complex there is a need to monitor whether the transmission state to be adjusted, determined from the transmitted information, has been correctly selected or whether the item(s) of decision information—on the basis of which the transmission state to be adjusted is selected—is correct.
Currently, the adaptation of the transmission states to decision information such as for example the channel quality is only measured indirectly or statistically using the transmitted data rate. For example, data are transmitted to a radio device to be tested and the channel quality is varied over time. In the simplest case, the channel quality is continuously improved e.g., linearly as time progresses starting from a very poor channel quality and the data rate of the transmitted data is measured. The data rate depends upon for example the selected modulation type and thus permits an indirect inference of the actually used transmission state. If the adaptation of the transmission states functions effectively, higher data rates for each channel quality are obtained than for poor adaptations. The function of the channel quality over time can be varied ever further in order to simulate fluctuations in the channel quality as occur in reality. Therefore, e.g. fading oscillations are simulated in the German patent specification DE 100 25 838 B4 by a Monte Carlo method.
A first problem associated with the indirect measurement of the transmission state adaptation is that the data rate does not show a great deal of interesting information such as for example the occurrence rate of the transmission state changes, or which transmission states are assumed or how these develop over time.
A second problem is that owing to the described measuring methods of the Prior Art, problem regions, such as for example switching points at which a change is made from one transmission state to another, cannot be tested individually and specifically.